Surging and popping on acceleration (#2)
07-17-2013, 08:49 AM
#1
Surging and popping on acceleration (#2)
I have this thread started in the Jetcat folder but thought I'd shop it around a little more widely. I could REALLY use some help and I think others out there are having the same trouble:
http://www.rcuniverse.com/forum/m_11...m.htm#11571324
Please read through to the end.
Mitch
http://www.rcuniverse.com/forum/m_11...m.htm#11571324
Please read through to the end.
Mitch
07-17-2013, 09:43 AM
#2
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RE: Surging and popping on acceleration (#2)
Mitch, I guess I have bad news for you [>:]
I also fly at high density altitude conditions.
When they don't work, they don't work !!!! No matter what you do.
If you trick them to work on the ground, they will stagnate on the air at the worst place.
It doesn't matter if it is a brand new engine model, or an old one.
The ones that work, will continue working regardless of age.
It could be related to tolerances in manufacture, I guess. Fuel to air ratio is at the edge of the feasible zone.
We have done hours of testing, parameters change, turbine blades twitching (at the factory of course), fuel change, etc, etc .... no luck.
Moral: take good care of the ones that work at your hot and humid field
Jack
I also fly at high density altitude conditions.
When they don't work, they don't work !!!! No matter what you do.
If you trick them to work on the ground, they will stagnate on the air at the worst place.
It doesn't matter if it is a brand new engine model, or an old one.
The ones that work, will continue working regardless of age.
It could be related to tolerances in manufacture, I guess. Fuel to air ratio is at the edge of the feasible zone.
We have done hours of testing, parameters change, turbine blades twitching (at the factory of course), fuel change, etc, etc .... no luck.
Moral: take good care of the ones that work at your hot and humid field
Jack
07-17-2013, 10:21 AM
#4
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RE: Surging and popping on acceleration (#2)
Have you tried to change the fuel you are using?
Are you using a bypass and /or fod screen?
Have you already rised the idle in 5Krpm?
Are you using a bypass and /or fod screen?
Have you already rised the idle in 5Krpm?
07-17-2013, 10:34 AM
#5
RE: Surging and popping on acceleration (#2)
Thanks to Jack and erbroens for a quick response.
Jack, I really enjoyed and appreciate your response. I know you are correct about these engines (I think especially the small form-factor engines putting out big thrust like my Titan) being on the ragged edge of civilized behavior.
erbroens, I had already thought about a fuel change/modification to see if it would help the accel problem. I wonder what a little gasoline would do? I know from full scale experience it won't hurt the engine for a short time and especially if just used as an additive. If not gasoline I wonder what other additive might help? I'm using K1 kero btw. Can't imagine why it wouldn't work fine in the first place.
I haven't raised the idle because I would NOT like the extra residual thrust on my Ultra Flash.
Jack, I really enjoyed and appreciate your response. I know you are correct about these engines (I think especially the small form-factor engines putting out big thrust like my Titan) being on the ragged edge of civilized behavior.
erbroens, I had already thought about a fuel change/modification to see if it would help the accel problem. I wonder what a little gasoline would do? I know from full scale experience it won't hurt the engine for a short time and especially if just used as an additive. If not gasoline I wonder what other additive might help? I'm using K1 kero btw. Can't imagine why it wouldn't work fine in the first place.
I haven't raised the idle because I would NOT like the extra residual thrust on my Ultra Flash.
07-17-2013, 10:56 AM
#6
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RE: Surging and popping on acceleration (#2)
Mitch, we have tried adding some gasoline and it does help some.
But, needless to say, be careful. Gasoline is much more flammable than kero. Any spark can mean trouble.
jack
But, needless to say, be careful. Gasoline is much more flammable than kero. Any spark can mean trouble.
jack
07-17-2013, 02:58 PM
#10
RE: Surging and popping on acceleration (#2)
Hi Mitch.
I have had a quick read though both threads.
It doesn't look like you have tried a different ECU and fuel pump.
I would change these out first so at least you can point your finger at the engine itself if it still gives trouble.
Remove all filters and valves if you can so you can eliminate as many variables as possible.
Also I couldn't tell if you were bench running it or running it in the aircraft.
I would like to see it bench run so you can eliminate airflow issues that could be induced in fuselage.
Mate I hope you can get this sorted. It know how much it does your head in when an engine is not running properly!!
EDIT:Maybe it would just be easier to send it for a JetCat service?
Paul.
I have had a quick read though both threads.
It doesn't look like you have tried a different ECU and fuel pump.
I would change these out first so at least you can point your finger at the engine itself if it still gives trouble.
Remove all filters and valves if you can so you can eliminate as many variables as possible.
Also I couldn't tell if you were bench running it or running it in the aircraft.
I would like to see it bench run so you can eliminate airflow issues that could be induced in fuselage.
Mate I hope you can get this sorted. It know how much it does your head in when an engine is not running properly!!
EDIT:Maybe it would just be easier to send it for a JetCat service?
Paul.
07-17-2013, 03:45 PM
#11
RE: Surging and popping on acceleration (#2)
Maybe it would just be easier to send it for a JetCat service?
07-17-2013, 04:08 PM
#12
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RE: Surging and popping on acceleration (#2)
hi mitch
i know the problems of these engines
they are a pain in the ass because they are wrong build
it only needs a different diffusor
a radial one
its very simple , the engine needs air , but dont get it because of the wrong diffusor build
but i am sorry to say , i cant help you at the moment because i am very bussy , and i dont have the machines anymore to make them
but then you know what is the problem
regards
Martin.
i know the problems of these engines
they are a pain in the ass because they are wrong build
it only needs a different diffusor
a radial one
its very simple , the engine needs air , but dont get it because of the wrong diffusor build
but i am sorry to say , i cant help you at the moment because i am very bussy , and i dont have the machines anymore to make them
but then you know what is the problem
regards
Martin.
07-17-2013, 04:59 PM
#13
RE: Surging and popping on acceleration (#2)
ORIGINAL: paulhat
Hi Mitch.
I have had a quick read though both threads.
It doesn't look like you have tried a different ECU and fuel pump.
I would change these out first so at least you can point your finger at the engine itself if it still gives trouble.
Remove all filters and valves if you can so you can eliminate as many variables as possible.
Also I couldn't tell if you were bench running it or running it in the aircraft.
I would like to see it bench run so you can eliminate airflow issues that could be induced in fuselage.
Mate I hope you can get this sorted. It know how much it does your head in when an engine is not running properly!!
EDIT:Maybe it would just be easier to send it for a JetCat service?
Paul.
Hi Mitch.
I have had a quick read though both threads.
It doesn't look like you have tried a different ECU and fuel pump.
I would change these out first so at least you can point your finger at the engine itself if it still gives trouble.
Remove all filters and valves if you can so you can eliminate as many variables as possible.
Also I couldn't tell if you were bench running it or running it in the aircraft.
I would like to see it bench run so you can eliminate airflow issues that could be induced in fuselage.
Mate I hope you can get this sorted. It know how much it does your head in when an engine is not running properly!!
EDIT:Maybe it would just be easier to send it for a JetCat service?
Paul.
I'm not in a hurry to send it back to JC. I don't really want to spend a bunch of money on this engine because of it's age. I'd rather spend that money on a new Kingtech and fix my old JC just for fun.
Thanks for the advice.
Mitch
07-18-2013, 03:10 AM
#15
RE: Surging and popping on acceleration (#2)
ORIGINAL: airraptor
how does the jet man get his to work when he jumps out of planes at 10-12,000 feet?
how does the jet man get his to work when he jumps out of planes at 10-12,000 feet?
He's using brand spanking new engines (if he smart) that are working just right. It's that or die.
07-18-2013, 03:21 AM
#16
RE: Surging and popping on acceleration (#2)
ORIGINAL: frema
hi mitch
i know the problems of these engines
they are a pain in the ass because they are wrong build
it only needs a different diffusor
a radial one
its very simple , the engine needs air , but dont get it because of the wrong diffusor build
but i am sorry to say , i cant help you at the moment because i am very bussy , and i dont have the machines anymore to make them
but then you know what is the problem
regards
Martin.
hi mitch
i know the problems of these engines
they are a pain in the ass because they are wrong build
it only needs a different diffusor
a radial one
its very simple , the engine needs air , but dont get it because of the wrong diffusor build
but i am sorry to say , i cant help you at the moment because i am very bussy , and i dont have the machines anymore to make them
but then you know what is the problem
regards
Martin.
07-18-2013, 04:48 AM
#17
My Feedback: (5)
RE: Surging and popping on acceleration (#2)
ORIGINAL: mitchilito
Not sure why I would want to do that. It starts up just great.
ORIGINAL: basimpsn
Do a video of the engine during startup.
Do a video of the engine during startup.
The Engine would start and idle but as it throttle up the engine hangs up
Another cause could be a fuel ring leak.
Or missing restrictor between the bearing lub pipe
compressor touching compressor housing
restrictor needed for the fuel ring.
All the about is JUST MY OPINION
07-18-2013, 05:04 AM
#18
RE: Surging and popping on acceleration (#2)
ba, thanks for all that info. I'm going to chase every one of these ideas down till I fix this dang thing! I sure wish I had a spare pump to scab in there.
Anybody have a spare pump kicking around they'd be willing to lend me?
Mitch
Anybody have a spare pump kicking around they'd be willing to lend me?
Mitch
07-18-2013, 05:08 AM
#19
RE: Surging and popping on acceleration (#2)
ba, thanks for all that info. I'm going to chase every one of these ideas down till I fix this dang thing! I sure wish I had a spare pump to scab in there.
Anybody have a spare pump kicking around they'd be willing to lend me?
Mitch
Anybody have a spare pump kicking around they'd be willing to lend me?
Mitch
07-19-2013, 10:24 AM
#22
RE: Surging and popping on acceleration (#2)
Latest update: I tried several things to eliminate the popping:
Mixed about 10% gasoline with my K1
Adjusted the fuel needles in the vapor tubes
Even put an .008 shim under the compressor wheel to move it closer to the shroud
None of it helped. So I'm throwing in the towel and sending it off to JC for zero time treatment
Hey, it was all a bunch of fun and thanks to all my RCU brothers for the fantastic advice. I learned a LOT about my Titan
Mitch in NC
Mixed about 10% gasoline with my K1
Adjusted the fuel needles in the vapor tubes
Even put an .008 shim under the compressor wheel to move it closer to the shroud
None of it helped. So I'm throwing in the towel and sending it off to JC for zero time treatment
Hey, it was all a bunch of fun and thanks to all my RCU brothers for the fantastic advice. I learned a LOT about my Titan
Mitch in NC
07-19-2013, 11:27 AM
#23
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RE: Surging and popping on acceleration (#2)
Mitch ...... been there done that with more than 10 engines.
If it isn't working, it won't work [:@][:@]
If it works on the ground, it will quit while flying.
Not worth risking the airplane !
Try it on a dry and cool place, and you will see that it works like a jewel. Some of them just can't take hot and humid environments.
BTW, I honestly hope that I am wrong. So, if somebody has a proven answer (not a theory, or asking you to change components) please chime in.
Jack
Edit: I should mention that half of those engines (some of them brand new) were sent to CA for inspection and fix. They run perfect there, but no change here (hot, humid and 1500ft).
If it isn't working, it won't work [:@][:@]
If it works on the ground, it will quit while flying.
Not worth risking the airplane !
Try it on a dry and cool place, and you will see that it works like a jewel. Some of them just can't take hot and humid environments.
BTW, I honestly hope that I am wrong. So, if somebody has a proven answer (not a theory, or asking you to change components) please chime in.
Jack
Edit: I should mention that half of those engines (some of them brand new) were sent to CA for inspection and fix. They run perfect there, but no change here (hot, humid and 1500ft).
07-19-2013, 01:14 PM
#24
RE: Surging and popping on acceleration (#2)
ORIGINAL: Jack Diaz
Mitch ...... been there done that with more than 10 engines.
If it isn't working, it won't work [:@][:@]
If it works on the ground, it will quit while flying.
Not worth risking the airplane !
Try it on a dry and cool place, and you will see that it works like a jewel. Some of them just can't take hot and humid environments.
BTW, I honestly hope that I am wrong. So, if somebody has a proven answer (not a theory, or asking you to change components) please chime in.
Jack
Edit: I should mention that half of those engines (some of them brand new) were sent to CA for inspection and fix. They run perfect there, but no change here (hot, humid and 1500ft).
Mitch ...... been there done that with more than 10 engines.
If it isn't working, it won't work [:@][:@]
If it works on the ground, it will quit while flying.
Not worth risking the airplane !
Try it on a dry and cool place, and you will see that it works like a jewel. Some of them just can't take hot and humid environments.
BTW, I honestly hope that I am wrong. So, if somebody has a proven answer (not a theory, or asking you to change components) please chime in.
Jack
Edit: I should mention that half of those engines (some of them brand new) were sent to CA for inspection and fix. They run perfect there, but no change here (hot, humid and 1500ft).
